On the TeXLive mailing list, Norbert Preining <prein...@logic.at>, one of the maintainers of TeXLive posted the following today.
With the end of 2019, Python2 will be deprecated and not receive any security updates. Most distributions will throw out Python2 completely. (Don't ask me about my opinion on the whole Py2/Py3 mess ...) We have quite a lot of scripts in TeX Live that are Python2 only, and we should seriously do some work on getting that fixed, rather soon. I have started a list of packages/scripts I found that require python, and tried to check which version they need, see below list. If you are the maintainer of any of these packages, and still are using Python2, please try to update to Python3 as soon as possible. ... lilyglyphs/ py2 only lilyglyphs/lily-glyph-commands.py lilyglyphs/lily-image-commands.py lilyglyphs/lily-rebuild-pdfs.py lilyglyphs/lilyglyphs_common.py ... This package is written by Urs Liska <u...@openlilylib.org>, who is quite busy these days. In case you have experience with Python 2 to 3 conversion, please help produce a new version! Werner